Among those new developments is the possibility that the U.S. may never build a permanent storage facility for spent fuel as had been planned for Nevada’s Yucca Mountain; or the increased possibility of “fuel pool fires” — things the original rule, called “waste confidence,” had never envisioned.

“The Nuclear Regulatory Commission’s (NRC) approval of the Continued Storage Rule is another step forward in the license renewal process for Limerick Generating Station,” Dana Melia, communications manager for the plant, wrote in an email responding to a Mercury request for comment.

The issuing of this document, which addresses issues raised during a 2011 public hearing held in Sunnybrook Ballroom and during a public comment period, is a crucial step forward for Exelon Nuclear in its application to extend the license of the 28-year-old Limerick Generating Station.

Currently the operating licenses on the plant’s two nuclear reactors expire Oct. 26, 2024 for Unit 1, and June 22, 2029 for Unit 2.

“The final step on the part of the NRC regarding the Limerick license renewal application will be a decision by the Director of the Office of Nuclear Reactor Regulation on whether to approve or disapprove it,” Sheehan wrote in an email response to an inquiry by The Mercury.

However, no date for that decision has been set.

Its worth noting that, to date, the NRC has never denied a relicensing application for any operating nuclear plant in the United States.

One remaining complication is a legal challenge from the Natural Resources Defense Council.

It is unclear what, if any, affect that review will have on the relicensing decision.

Despite rejecting NRDC’s contention, the NRC did instruct its staff to address many of the concerns raised in the legal action in the final environmental impact statement, Sheehan wrote.

Sheehan said the staff concluded in that document that “the adverse environmental impacts of license renewal for (Limerick Generating Station) are not great enough to deny the option of license renewal for energy planning decision-makers.”

“Limerick’s license renewal application is strong and on track. As part of the license renewal process, the NRC has performed a comprehensive evaluation of the thousands of actions and equipment upgrades Exelon has performed at Limerick to ensure continued safe and reliable operations through the extended period,” Melia wrote. “We look forward to the NRCs final decision on Limerick’s license renewal application.”